Methods and devices for cutting tissue

ABSTRACT

A catheter which includes a cutting element having one or more raised elements is provided. The cutting element has a cup-shaped surface at the distal end that may be smooth and continuous except for the raised elements. The raised elements have a surface that tends to direct cut particles of material towards one or more of the axis of rotation of the cutting element, the catheter axis, or a particle collection chamber. In further aspects of the invention, a cutting element oscillates in a direction roughly parallel to the axis of rotation of the cutting element.

This application claims the benefit of U.S. Provisional PatentApplication No. 61/265,863, filed Dec. 2, 2009, entitled “Methods andDevices for Cutting Tissue”, the contents of which are herebyincorporated by reference herein.

FIELD OF THE INVENTION

The present invention is directed to cutting elements for an atherectomycatheter and methods of cutting material from a blood flow lumen using arotating cutting element.

BACKGROUND OF THE INVENTION

Catheters are used to remove unwanted tissue from the body. Atherectomycatheters are used to remove material from a blood vessel to open theblood vessel and improve blood flow through the vessel.

One problem that occurs when removing material from a blood vessel isthat the material may be either soft or hard and may vary during thecutting process. As such, the cutting element should be able to cut bothhard tissue and soft tissue. Another problem that occurs when using arotating cutter is that particles of material tend to be displaced in adirection tangential to the cutter, away from the catheter and away fromcatheter based particle collection structures. It is therefore alsodesirable to direct cut particles towards the catheter, and especiallytowards a catheter based particle collection structure.

SUMMARY OF THE INVENTION

The invention provides an atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; a cutting element coupled to the rotatable shaft for rotatingthe cutting element about an axis of rotation, the cutting elementhaving a cup-shaped surface and a cutting edge, the cup-shaped surfacebeing configured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction; anda raised element extending outwardly from the cup-shaped surface of thecutting element, the raised element being configured to direct cutparticles of material towards one of more of the axis of rotation of thecutting element, a catheter longitudinal axis, or the tissue collectionchamber.

The invention provides an atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; and a cutting element coupled to the rotatable shaft forrotating the cutting element about an axis of rotation, the cuttingelement having a cutting edge, and the cutting element being configuredto oscillate in a direction substantially parallel to the axis ofrotation of the cutting element.

The invention provides a method of removing material from a body lumen,the method comprising providing an atherectomy catheter, the atherectomycatheter comprising: a body having an opening; a rotatable shaft coupledto the body; a tissue collection chamber coupled to the body andpositioned distal to the cutting element; a cutting element coupled tothe rotatable shaft for rotating the cutting element about an axis ofrotation, the cutting element having a cup-shaped surface and a cuttingedge, the cup-shaped surface being configured to re-direct tissue cut bythe cutting edge in a distal direction when the cup-shaped surface movesin the distal direction; and a raised element extending outwardly fromthe cup-shaped surface of the cutting element, the raised element beingconfigured to direct cut particles of material towards one of more ofthe axis of rotation of the cutting element, a catheter longitudinalaxis, or the tissue collection chamber; placing the catheter in the bodylumen; and moving the catheter in the body lumen to contact the cuttingelement with the material in the body lumen.

The invention provides a method of removing material from a body lumen,the method comprising: providing an atherectomy catheter, theatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; and a cutting elementcoupled to the rotatable shaft for rotating the cutting element about anaxis of rotation, the cutting element having a cutting edge, and thecutting element being configured to oscillate in a directionsubstantially parallel to the axis of rotation of the cutting element;placing the catheter in the body lumen; and moving the catheter in thebody lumen to contact the cutting element with the material in the bodylumen. In one embodiment, the catheter is moved in a distal direction tocontact the cutting edge with the material in the body lumen.

These and other aspects of the invention will become apparent from thefollowing description of the preferred embodiments, drawings and claims.The details of one or more embodiments of the invention are set forth inthe accompanying drawings and in the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an isometric view of a distal end of an atherectomycatheter.

FIG. 2 is an isometric cross-sectional view of a portion of theatherectomy catheter of FIG. 1 with a cutting element in a storedposition.

FIG. 3 is an isometric cross-sectional view of a portion of theatherectomy catheter of FIG. 1 with a cutting element in a workingposition.

FIG. 4 shows an isometric view of an embodiment of a cutting element.

FIG. 5 shows an end view of an embodiment of a cutting element.

FIG. 6 is an isometric cross-sectional view of an embodiment of acutting element.

FIG. 7 shows an end view of another embodiment of a cutting element,which may be used with the atherectomy catheter shown in FIG. 1.

FIG. 8 shows an isometric view of the embodiment of the cutting elementillustrated in FIG. 7.

FIG. 8A shows an isometric view of one of the raised elements of thecutting element embodiment illustrated in FIG. 8.

FIG. 9 shows an end view of another embodiment of a cutting element,which may be used with the atherectomy catheter shown in FIG. 1.

FIG. 10 shows an isometric view of the embodiment of the cutting elementillustrated in FIG. 9.

FIG. 10A shows an isometric view of one of the raised elements of thecutting element embodiment illustrated in FIG. 10.

FIG. 11 shows an isometric view of a modified version of the embodimentof the cutting element illustrated in FIG. 8.

FIG. 11A shows an isometric view of one of the raised elements of thecutting element embodiment illustrated in FIG. 11.

FIG. 12 illustrates an isometric cross-sectional view of a portion of anatherectomy catheter having a cutting element that oscillates in adirection generally along the axis of the cutting element.

FIG. 13 illustrates an isometric view of a component of the cathetershown in FIG. 12.

DETAILED DESCRIPTION

The invention provides an atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; a cutting element coupled to the rotatable shaft for rotatingthe cutting element about an axis of rotation, the cutting elementhaving a cup-shaped surface and a cutting edge, the cup-shaped surfacebeing configured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction; anda raised element extending outwardly from the cup-shaped surface of thecutting element, the raised element being configured to direct cutparticles of material towards one of more of the axis of rotation of thecutting element, a catheter longitudinal axis, or the tissue collectionchamber. In an embodiment, the raised element is configured to directcut particles of material towards the axis of rotation of the cuttingelement. In one embodiment, the cutting edge is at a radially outer edgeof the cutting element. In an embodiment, the raised element comprises acurved raised element cutting edge. In an embodiment, the raised elementcomprises a first wall that extends from the curved raised elementcutting edge to the cup-shaped surface, the first wall directing the cutparticles of material towards the axis of rotation of the cuttingelement.

In an embodiment, the first wall curves from a relatively tangentialangle with the cutting edge at the radially outer edge of the cuttingelement to a relatively radial angle closer to the axis of rotation ofthe cutting element. In one embodiment, the raised element comprises adistal wall that extends from the first, curved raised element cuttingedge to a second edge, the distal wall forming an angle of less than 90degrees with respect to the axis of rotation of the cutting element. Inan embodiment, the first, curved raised element cutting edge is moredistal than the second edge. In one embodiment, the minimum radialdistance between the first, curved raised element cutting edge and thecutting edge of the cutting element is less than the minimum radialdistance between the second edge and the cutting edge of the cuttingelement. In one embodiment, wherein an included angle between the firstwall and the distal wall is an obtuse angle.

In one embodiment, the raised element is recessed proximally from thecutting edge by a longitudinal distance. For example, the raised elementcan be recessed proximally from the cutting edge by a longitudinaldistance of 0.0010 to 0.0050 inch (0.0025 to 0.0127 cm). In anembodiment, the raised element is recessed from the cutting edge by aradial distance of 0.0010 to 0.0050 inch (0.0025 to 0.0127 cm).

In one embodiment, the raised element comprises a first wall thatextends from a raised element cutting edge to the cup-shaped surface,the first wall directing the cut particles of material towards the axisof rotation of the cutting element and wherein the first wall forms anacute angle with the cup-shaped surface to form an undercut. In anembodiment, the raised element comprises a distal wall that extends fromthe first raised element cutting edge to a second edge, the distal wallforming an angle of less than 90 degrees with respect to the axis ofrotation of the cutting element. In one embodiment, the first raisedelement cutting edge is more distal than the second edge. In anembodiment, the minimum radial distance between the first raised elementcutting edge and the cutting edge of the cutting element is less thanthe minimum radial distance between the second edge and the cutting edgeof the cutting element. In an embodiment, a wall having a rake angle isinterspersed between the intersection of the first wall and the distalwall. In one embodiment, the rake angle is negative.

In an embodiment, the cup-shaped surface of the cutting element issmooth and uninterrupted throughout at least 300 degrees when viewedalong the axis of rotation of the cutting element. In one embodiment,the cup-shaped surface of the cutting element is smooth anduninterrupted for at least 90% of the surface area of the cuttingelement when viewed along the axis of rotation of the cutting element.In an embodiment, the cup-shaped surface of the cutting element has anouter radius when viewed along the axis of rotation of the cuttingelement, the cup-shaped surface being continuous and uninterrupted fromthe axis of rotation to at least half the distance to the outer radius.In one embodiment, the atherectomy catheter further comprises aplurality of raised elements, the plurality of raised elementsaltogether occupying an area less than 60 degrees and less than 5% ofthe surface area when viewed along the axis of rotation of the cuttingelement, and the cup-shaped surface being smooth and uninterrupted forat least 90% of the surface area. In one embodiment, the atherectomycatheter comprises a plurality of raised elements extending outwardlyfrom the cup-shaped surface, the plurality of raised elements being 1,2, 3, 4, 6, or 8 raised elements.

In one embodiment, the cutting element is movable between a storedposition and a cutting position relative to the opening. In anembodiment, the cutting element is moved between the stored position andthe cutting position by sliding the cutting element against a camsurface. In an embodiment, a distal portion of the catheter relative toa proximal portion is deflected by sliding the cutting element againstthe cam surface. In an embodiment, the cutting element is configured tooscillate in a direction substantially parallel to the axis of rotationof the cutting element.

The invention provides an atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; and a cutting element coupled to the rotatable shaft forrotating the cutting element about an axis of rotation, the cuttingelement having a cutting edge, and the cutting element being configuredto oscillate in a direction substantially parallel to the axis ofrotation of the cutting element. In one embodiment, the atherectomycatheter comprises a ramp having one or more recesses, the cuttingelement comprises one or more raised portions on a cam surface of thecutting element, the one or more raised portions fitting within the oneor more recesses when the raised portions and the recesses are aligned,and the raised portions leaving and entering the recesses as the cuttingelement is rotated and thereby causing the cutting element to oscillate.In one embodiment, the atherectomy catheter comprises a ramp having oneor more raised portions, the cutting element comprises one or morerecesses on a cam surface of the cutting element, the one or more raisedportions fitting within the one or more recesses when the raisedportions and the recesses are aligned, and the raised portions leavingand entering the recesses as the cutting element is rotated and therebycausing the cutting element to oscillate. In one embodiment, theatherectomy catheter comprises a ramp having one or more raisedportions, the cutting element comprises one or more raised portions on acam surface of the cutting element, and the raised portions causing thecutting element to oscillate as the cutting element is rotated.

In one embodiment, the cutting element has a cup-shaped surface, thecup-shaped surface being configured to re-direct tissue cut by thecutting edge in a distal direction when the cup-shaped surface moves inthe distal direction. In an embodiment, the cutting edge is a radiallyouter edge of the cutting element. In an embodiment, the cathetercomprises a raised element extending outwardly from the cup-shapedsurface of the cutting element. In an embodiment, the cutting edge is aradially outer edge of the cutting element, and the raised element isrecessed proximally from the cutting edge when viewed along the axis ofrotation of the cutting element. In one embodiment, the cutting elementis movable between a stored position and a cutting position relative tothe opening. In one embodiment, the cutting element is moved between thestored position and the cutting position by sliding the cutting elementagainst a cam surface. In one embodiment, a distal portion of thecatheter relative to a proximal portion is deflected by sliding thecutting element against the cam surface.

The invention provides a method of removing material from a body lumen,the method comprising providing an atherectomy catheter, the atherectomycatheter comprising: a body having an opening; a rotatable shaft coupledto the body; a tissue collection chamber coupled to the body andpositioned distal to the cutting element; a cutting element coupled tothe rotatable shaft for rotating the cutting element about an axis ofrotation, the cutting element having a cup-shaped surface and a cuttingedge, the cup-shaped surface being configured to re-direct tissue cut bythe cutting edge in a distal direction when the cup-shaped surface movesin the distal direction; and a raised element extending outwardly fromthe cup-shaped surface of the cutting element, the raised element beingconfigured to direct cut particles of material towards one of more ofthe axis of rotation of the cutting element, a catheter longitudinalaxis, or the tissue collection chamber; placing the catheter in the bodylumen; and moving the catheter in the body lumen to contact the cuttingelement with the material in the body lumen. In one embodiment, thecatheter is moved in a distal direction to contact the cutting edge withthe material in the body lumen. In one embodiment, the catheter isplaced in the body lumen with the cutting element in the stored positionand the catheter is moved to contact the material with the cuttingelement in a cutting position. In one embodiment, the body lumen is ablood vessel.

The invention provides a method of removing material from a body lumen,the method comprising: providing an atherectomy catheter, theatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; and a cutting elementcoupled to the rotatable shaft for rotating the cutting element about anaxis of rotation, the cutting element having a cutting edge, and thecutting element being configured to oscillate in a directionsubstantially parallel to the axis of rotation of the cutting element;placing the catheter in the body lumen; and moving the catheter in thebody lumen to contact the cutting element with the material in the bodylumen. In one embodiment, the catheter is moved in a distal direction tocontact the cutting edge with the material in the body lumen. In anembodiment, the catheter is placed in the body lumen with the cuttingelement in the stored position and the catheter is moved to contact thematerial with the cutting element in a cutting position. In anembodiment, the body lumen is a blood vessel.

The present invention provides an atherectomy catheter which has acutting element that is able to cut both soft tissue and hard tissue.The cutting element has a sharp cutting edge that surrounds a cup-shapedsurface. The cup-shaped surface directs the material which has been cutinto a tissue chamber. The circumferential cutting edge and thecup-shaped surface together are well suited to cut and remove relativelysoft tissue.

In one aspect of the invention, an atherectomy catheter is providedwhich has one or more raised elements extending from the cup-shapedsurface. The raised element may be recessed longitudinally and radiallyfrom the outer cutting edge by a controlled distance such as0.0010-0.0020 inch (0.0025 to 0.0051 cm) but may in other embodiments becloser or further from the outer cutting edge depending upon theapplication. The raised elements help to break up hard tissue such ascalcified plaque. The raised elements are somewhat recessed from thedistal end so that the cutting edge remains exposed to cut soft tissue.When the cutting element encounters tissue which is too hard to be cutsufficiently by the cutting edge, the raised elements help to break theharder tissue with a more blunt application of force.

In another aspect of the invention, the raised element is somewhat smallso that a relatively large portion of the cup-shaped surface is smoothand uninterrupted. In this manner, the ability of the cutting element todirect tissue into the tissue chamber with the cup-shaped surface is notoverly inhibited by the raised elements. For example, the raisedelements may occupy an area less than 60 degrees when viewed along thelongitudinal axis. Stated another way, the cup-shaped surface of thecutting element is smooth and uninterrupted throughout at least 300degrees when viewed along the longitudinal axis. Stated still anotherway, the cup-shaped surface may be smooth and uninterrupted for at least95% of the surface area of the cutting element when viewed along thelongitudinal axis.

In yet another aspect of the invention, the raised element has a surfacethat tends to direct cut particles of material towards one or more ofthe axis of rotation of the cutter, the catheter axis, or a particlecollection chamber.

In further aspects of the invention, the cutter oscillates in adirection roughly parallel to the axis of the cutter so as to impart aforce on cut particles of material that directs them in a distaldirection, towards a collection chamber, or in both directions.

Referring to FIGS. 1 to 4, an atherectomy catheter 2 is shown which hasa cutting element 4, which is used to cut material from a blood flowlumen. The cutting element 4 is movable between a stored position (FIG.2) and a cutting position (FIG. 3) relative to an opening 6 in a body 8of the catheter 2. The cutting element 8 moves outwardly relative to theopening 6 so that a portion of the element 4 extends outwardly from thebody 8 through the opening 6. The cutting element 4 may be positionedrelative to the body 8 and opening 6 so that less than 90 degrees of thecutting element 4 is exposed to cut tissue. Of course, more of thecutting element 4 may be exposed without departing from numerous aspectsof the invention.

Catheter 2 may have a maximum size of 3, 4, 5, 6, 7, 8, 9, 10, or 12French (1, 1.3, 1.7, 2, 2.3, 2.7, 3, 3.3, or 4 mm) and may have aworking length ranging of 20, 30, 40, 60, 80, 100, 120, 150, 180 or 210cm depending on the requirements of the anatomical location in which useof the catheter is contemplated. Cutter 4 preferably has a diameterslightly less than that of the maximum size of catheter 2, typically0.010″ (0.025 cm), 0.015″ (0.038 cm), 0.020″ (0.051 cm), 0.025″ (0.064cm) or 0.030″ (0.076 cm) less. However these relative dimensions are notmeant to be limiting.

The catheter 2 is moved distally through a vessel with the cuttingelement 4 in the working or cutting position as described in furtherdetail below. As the catheter 2 moves through the blood vessel, thetissue is cut by the cutting element 4 and is directed into a tissuechamber 12 positioned distal to the cutting element 4. The tissuechamber 12 may be somewhat elongate to accommodate the tissue which hasbeen cut.

The cutting element 4 is moved proximally from the stored position sothat a cam surface 14 on the cutting element 4 engages a ramp 16 on thebody 8 of the catheter 2. The interaction between the cam surface 14 andthe ramp 16 causes the cutting element 4 to move to the cutting positionand also causes a tip 18 to deflect which tends to move the cuttingelement 4 toward the tissue to be cut.

The cutting element 4 is coupled to a shaft 20 that extends through alumen 21 in the catheter 2. The cutting element 4 is rotated about alongitudinal axis LA when the shaft rotates. The cutting element 4 isrotated at about 1 to 160,000 rpm but may be rotated at any othersuitable speed depending upon the particular application.

Referring to FIGS. 2, 4 and 5, the cutting element 4 is shown. The term“along the longitudinal axis” as used herein shall mean the view of FIG.5 that shows the distal end of the cutting element 4 when viewed in thedirection of the longitudinal axis and/or the axis of rotation. Thecutting element 4 has a cutting edge 22 that may be a continuous,uninterrupted, circular-shaped edge although it may also include ridges,teeth, serrations or other features without departing from the scope ofthe invention. The cutting edge 22 may be at a radially outer edge 23 ofthe cutting element 4 when the cutting element 4 is in the cuttingposition.

The cutting element 4 has a cup-shaped surface 24, which directs thetissue cut by the cutting edge 22 into the tissue chamber 12. Thecup-shaped surface 24 may be a smooth and continuous surface free ofthrough-holes, teeth, fins or other features, which disrupt the smoothnature of the surface 24 for at least half the distance from thelongitudinal axis LA to the outer radius at the cutting edge 22. Thecup-shaped surface 24 may also be free of any such features throughoutan area of at least 300 degrees relative to the longitudinal axis LA.

Cutter 4 may be comprised of steel, tungsten carbide, tungsten carbidecobalt, tungsten carbide molybdenum, silicon carbide, silicon nitride,ceramic, amorphous metals or other materials and may be manufactured bymethods including turning, grinding, sintering, electro-dischargemachining (EDM), laser cutting, heat treating, precipitation hardening,casting or other methods.

Referring to FIGS. 4 to 6, one or more raised elements 26 extendoutwardly from the cup-shaped surface 24 with FIG. 5 showing two raisedelements 26. The raised element 26 is a small wedge of material thatrises relatively abruptly from the cup-shaped surface 24. The raisedelement 26 has a first wall 30 and a second wall 32 that both extendradially and form an angle of about 20 degrees therebetween so that thetwo raised elements 26 together occupy an area of about 40 degrees andaltogether may be less than 60 degrees. A third wall 34 extends betweenthe radially inner portion of the first and second walls 30, 32. Theraised element 26 helps to break up hard tissue and plaque by applying arelatively blunt force to the hard tissue or plaque since cutting suchtissue with the cutting edge 22 is often not effective.

The raised elements 26 altogether occupy a relatively small part of thecup-shaped surface 24. The raised elements 26 together may occupy lessthan 5% of a surface area of the cutting element 4. The term “surfacearea of the cutting element” as used herein shall mean the surface areawhich is radially inward from the outer or cutting edge 22 and isexposed when viewed along the longitudinal axis LA. Stated another way,at least 95% of the surface area of the cutting element is a smoothcup-shaped surface when viewed along the longitudinal axis. By sizingand positioning the raised element 26 in this manner, the raised element26 does not interfere with the ability of the cutting element 4 to cutand re-direct tissue into the tissue chamber while still providing theability to break up hard tissue and plaque with the raised element 26.

The raised element 26 may be recessed from the cutting edge 22longitudinally and/or radially. The raised element 26 may be recessedlongitudinally (along axis LA) from the cutting edge 0.0010 to 0.0020inch (0.0025 to 0.0051 cm) and may be recessed about 0.0015 inch (0.0038cm). The raised element 26 may be recessed radially from the cuttingedge 22 by about the same amount. A distal wall 38 of the cuttingelement 4 forms a flat surface 40, which is perpendicular to thelongitudinal axis LA so that the entire surface is recessed the samedistance from the cutting edge. The distal wall 38 may take any othershape, such as a curved shape, or may be tilted, inclined or beveled asnow described.

Referring to FIGS. 7, 8 and 8A, another cutting element 4A is shownwherein the same or similar reference numbers refer to the same orsimilar structure and all discussion concerning the same or similarfeatures of the cutting element 4 are equally applicable here unlessnoted otherwise. The cutting element 4A has a cutting edge 22A that maybe a continuous, uninterrupted, circular-shaped edge although it mayalso include ridges, teeth, serrations or other features withoutdeparting from the scope of the invention. The cutting edge 22A may beat a radially outer edge 23A of the cutting element 4A when the cuttingelement 4A is in the cutting position. The cutting element 4A has acup-shaped surface 24A that directs the tissue cut by the cutting edge22A into the tissue chamber 12 (see FIG. 2). The cup-shaped surface 24Amay be a substantially smooth and continuous surface as described abovein connection with the cutting element 4.

One or more raised elements 26A extend outwardly from the cup-shapedsurface 24A. FIG. 8 shows four raised elements 26A but may include anynumber such as 1, 2, 3, 4, 6 or 8 raised elements. The raised element26A is a small wedge of material that rises relatively abruptly from thecup-shaped surface 24A. The raised element 26A has a first wall 30A anda second wall 32A which, in one embodiment, both extend radially andform an angle of about 1 to 30 degrees therebetween so that the fourraised elements 26A together occupy an area of about 4 to 60 degrees andaltogether may be less than 60 degrees. A third wall 34A extends betweenthe radially inner portion of the first and second walls 30A, 32A. Insome embodiments the raised elements 26A may occupy a relatively smallpart of the cup-shaped surface 24A and may be recessed from the cuttingedge 22A in the manner described above in connection with the cuttingelement 4. In other embodiments at least 60%, 70%, 80% or 90% of thesurface area of the cutting element is a smooth cup-shaped surface.

A distal wall 38A of the cutting element 4A has a surface 40A that formsan angle of about 30 to 90 degrees with respect to the longitudinal axisLA. The entire surface 40A may still be somewhat close to but recessedfrom the cutting edge 22A so that the entire surface 40A is at least0.0010, 0.0020, 0.0030, 0.0040 or 0.0050 inches (0.0025, 0.0051, 0.0076,0.0101, or 0.0127 cm) from the cutting edge. An edge 50 formed at theintersection of wall 30A and distal wall 38A is closer to the cuttingedge 22A than an edge 52 formed at the intersection of wall 32A anddistal wall 38A. The cutting element 4A may be rotated in eitherdirection so that the raised edge 50 may be the leading or trailingedge. In some embodiments the raised edge may be 0.0010 to 0.0020 inch(0.0025 to 0.0051 cm) from the cutting edge. The raised elements 26A mayall be formed in the same manner or may be different from one another.For example, some of the elements 26A could be angled in differentdirections so that two of the elements have the raised edge 50 as theleading edge and two of the elements 26A have the raised edge 50 as thetrailing edge. The raised elements 26A may also subtend differentangles, be of different heights or may have different radial lengthswithout departing from various aspects of the present invention.

Referring to FIGS. 9, 10 and 10A, another cutting element 4B is shownwherein the same or similar reference numbers refer to the same orsimilar structure and all discussion concerning the same or similarfeatures of the cutting element 4 are equally applicable here unlessnoted otherwise. The cutting element 4B has a cutting edge 22B that maybe a continuous, uninterrupted, circular-shaped edge although it mayalso include ridges, teeth, serrations or other features withoutdeparting from the scope of the invention. The cutting edge 22B may beat a radially outer edge 23B of the cutting element 4B when the cuttingelement 4B is in the cutting position. The cutting element 4B has acup-shaped surface 24B that directs the tissue cut by the cutting edge22B into the tissue chamber 12 (see FIG. 2). In one embodiment thecup-shaped surface 24B may be a substantially smooth and continuoussurface as described above in connection with the cutting element 4.

One or more raised elements 26B, extend outwardly from the cup-shapedsurface 24B. FIGS. 9 and 10 show four raised elements 26B but mayinclude any number such as 1, 2, 3, 4, 6 or 8 raised elements. Theraised element 26B is a small wedge of material that rises relativelyabruptly from the cup-shaped surface 24B and which subtends an arc ofabout 1 to 30 degrees relative to axis LA, the four raised elements 26Bsubtending an arc of about 4 to 60 degrees altogether. The raisedelement 26B has a first wall 30B that extends between a curved cuttingedge 50B and cup shaped surface 24B and also has a second wall 32B whichextends radially relative to axis LA. A third wall 34B extends betweenthe radially inner portion of the first and second walls 30B, 32B. Insome embodiments the raised elements 26B may occupy a relative smallpart of the cup-shaped surface 24B and may be recessed from the cuttingedge 22B in the manner described above in connection with the cuttingelement 4. In other embodiments at least 60%, 70%, 80% or 90% of thesurface area of the cutting element is a smooth cup-shaped surface.

A distal wall 38B of the cutting element 4B has a surface 40B that formsan angle of less than 90 degrees with respect to the longitudinal axisLA. In some embodiments the surface 40B is angled such that edge 50B ismore distal than edge 52B. The entire surface 40B may still be somewhatclose to but recessed from the cutting edge 22B so that the entiresurface 40B is from 0.0010 to 0.0050 inch (0.0025 to 0.0127 cm),including 0.0010, 0.0020, 0.0030, 0.0040 or 0.0050 inch (0.0025, 0.0051,0.0076, 0.0101, or 0.0127 cm), from the cutting edge. An edge 50B formedat the intersection of wall 30B and distal wall 38B is closer to thecutting edge 22B than an edge 52B formed at the intersection of wall 32Band distal wall 38B. The included angle between wall 30B and surface40B, in the vicinity of edge 50B, is greater than 90 degrees. Thecutting element 4B may be rotated in either direction so that the raisededge 50B may be the leading or trailing edge. In one embodiment, thecutter 4B is rotated in the direction of arrow R so that edge 50B is theleading edge. Raised edges 50B, 52B may be 0.0010 to 0.0020 inch (0.0025to 0.0051 cm) from the cutting edge. The raised elements 26B may all beformed in the same manner or may be different from one another. Forexample, some of the elements 26B could be angled in differentdirections so that two of the elements have the raised edge 50B as theleading edge and two of the elements 26A have the raised edge 50B as thetrailing edge. The raised elements 26B may also subtend differentangles, be of different heights or may have different radial lengthswithout departing from various aspects of the present invention.

In one embodiment cutter 4B is rotated in the direction of arrow R andpushed distally to force cup shaped surface 24B and raised elements 26Binto contact with material such as atheroma or plaque. Raised elements26B will tend to concentrate cutting force along edge 50B due to reliefangle between cutter axis LA and surface 40B. Cutter 4B will tend toscrape away material such as atheroma or plaque rather than cut intothis material due to the obtuse included angle between wall 30B andsurface 40B, in the vicinity of edge 50B. Material contacted by raisedelements 26B will tend to be directed towards axis LA by surface 30Bwhich curves from a relatively tangential angle near edge 22B to arelatively radial angle near edge 34B.

Referring to FIGS. 11 and 11A, another cutting element 4C is shown.Cutting element 4C is a modified version of cutting element 4A. Themodification consists of adding an undercut 41C to the leading face ofone or more raised element 26A, resulting in modified raised element26C. When cutter 4C is rotated in the direction of arrow T the undercutdirects particles of material into the concave cavity defined by cupshaped surface 24A of the cutter, and towards axis LA of the cutter.Optionally an undercut can be applied to the leading face of one or moreraised element 26, 26B of cutting elements 4, 4B respectively as well asto one or more raised elements 26A of cutting element 4A.

Undercut 41C is defined by wall 30C which is oriented at an acute angleto surface 40A, which intersects cup shaped surface 24A, and which meetswall 34A. The plane of wall 30C also intersects axis LA at less than 5,10, 15, or 20 degrees such that, when cutter 4C is spinning in directionT, particles of material tend to travel along wall 30C in directionsaway from cutting edge 22A and towards axis LA. In some embodiments wall43C may be interspersed between the intersection of wall 30C and wall40A. Wall 43C may be oriented at any desired rake angle, such as forexample a negative rake angle where the raised element will tend to notdig in to material being cut.

Use of the catheter 2 is now described in connection with the cuttingelement 4 but is equally applicable to use of the catheter 2 with eitherthe cutting element 4A, the cutting element 4B, or the cutting element4C. The catheter 2 is introduced into the patient in a conventionalmanner using a guidewire (not shown) or the like. The catheter 2 isadvanced with the cutting element in the stored position of FIG. 2 untilthe catheter is positioned proximal to the location where material is tobe removed. The cutting element 4 is then moved proximally so that theramp 16 and cam surface 14 engage to move the cutting element 4 to thecutting position of FIG. 3 and to deflect the tip of the catheter 2 tomove the cutting element 4 toward the tissue to be cut. The cuttingelement 4 is rotated about longitudinal axis LA and catheter 2 is thenmoved distally through the vessel so that the cutting element 4 cutstissue. The tissue, which has been cut, is directed into the tissuechamber 12 by the cup shaped surface 24, one or more raised elements 26,by curved surface 30B (of cutting element 4B), or by any combination ofa cup shaped surface, raised element, or curved surface.

More specifically, when using cutting element 4B and rotating thecutting element in the direction of arrow R (FIG. 9) cutting edge 22Bslices softer material and cup shaped surface directs the cut materialinto tissue chamber 12; the relief angle assures that distally directedforce on the catheter is concentrated at raised element edge 50B ratherthan distributed over surface 40B; raised elements 26B will tend toscrape away or pulverize harder material such as calcium due to theobtuse included angle between wall 30B and surface 40B in the vicinityof edge 50B; curved surface 30B directs material particles towardscutter axis LA; and curved surface 30B when rotating creates a fluidvortex that tends to direct material particles towards cutter axis LAand distally into tissue chamber 12.

More specifically, when using an undercut such as that shown for cuttingelement 4C and rotating the cutting element in the direction of arrow T(FIG. 11) undercut 41C directs material away from cutting edge 22A,along cup shaped surface towards axis LA, and radially towards axis LAof the cutting element.

In another embodiment, FIGS. 12 and 13 show atherectomy catheter 102having a cutting element 104 that oscillates in a direction generallyalong axis LA of the cutting element. Atherectomy catheter 102 issimilar to atherectomy catheter 2 wherein the same or similar referencenumbers refer to the same or similar structure and all discussionconcerning the same or similar features of the atherectomy catheter 2are equally applicable here unless noted otherwise.

Atherectomy catheter 102 is comprised of ramp 116 and cutter 104. Thecutting element 104 is moved proximally from the stored position (FIG.12) so that a cam surface 14 on the cutting element 104 engages a ramp116 on the body 8 of the catheter 102. The interaction between the camsurface 14 and the ramp 116 causes the cutting element 104 to move tothe cutting position (FIG. 3) and also causes a tip 18 to deflect whichtends to move the cutting element 104 toward the tissue to be cut.

Cutter 104 is comprised of one or more raised portions 14 a on camsurface 14; also ramp 116 is comprised of one or more recesses 116 a inramp surface 116 b. Recesses and raised portions are relativelydimensioned such that raised portion 14 a can fit within recess 116 a.Recess 116 a is also comprised of at least one edge 116 c. Cam surface14 of cutting element 104 is preloaded into pressured contact againstramp 116. In one embodiment catheter 102 is assembled with shaft 20 intension and catheter body 8 in compression by means known in the art toprovide such preload. In another embodiment catheter 102 is comprised ofa spring (not shown) that forces raised portion 14 a against rampsurface 116 b. Cutter 104 is comprised of cup shaped surface 24 andcutting edge 22 and may be comprised of zero, 1, 2, 3, 4, 6, or 8 raisedelements in any mixture or combination of raised elements 26, 26A, 26B,or 26C.

In an alternative embodiment (not shown) cutter 104 is comprised of oneor more recesses in cam surface 14 and ramp 116 is comprised of one ormore raised portions on ramp surface 116 b. In yet another embodiment(not shown) cutter 104 is comprised of one or more raised portions oncam surface 14 and ramp 116 is comprised of one or more raised portionson ramp surface 116 b.

In use catheter 102 is introduced into the patient in a conventionalmanner using a guidewire (not shown) or the like. The catheter 2 isadvanced with the cutting element in the stored position of FIG. 12until the catheter is positioned at the location where material is to beremoved. The cutting element 104 is then moved proximally so that theramp 116 and cam surface 14 engage to move the cutting element 104 tothe cutting position and to deflect the tip of the catheter 2 to movethe cutting element 104 toward the tissue to be cut (FIG. 3). Thecutting element 104 is rotated about longitudinal axis LA and catheter102 is then moved distally through the vessel so that the cuttingelement 104 cuts tissue. The tissue, which has been cut, is directedinto the tissue chamber 12 by cup shaped surface 24. While the cuttingelement 104 is rotated about longitudinal axis LA (in, for example, thedirection of arrow S) raised portions 14 a will slide along surface 116b of ramp 116 until the preload of cutter 104 against ramp 116 causesraised portion 14 a to enter into recess 116 a of ramp 116. Furtherrotation of cutting element 104 causes raised portion 14 a to contactrecess edge 116 c and be ejected from recess 116 a of ramp 116 therebyproducing a hammer-like impact of cutter 104 against the material to beremoved. In the case where the material to be removed has brittlecharacteristics, the material will be crushed into smaller particlesthereby facilitating its removal. Repeated rotation of cutter 104 willproduce repeated hammer-like blows of the cutter 104 against thematerial to be removed. The oscillations in a direction roughly parallelto the axis of the cutting element impart a force on cut particles ofmaterial that directs them in a distal direction, towards a collectionchamber, or in both directions.

The above description and the drawings are provided for the purpose ofdescribing embodiments of the invention and are not intended to limitthe scope of the invention in any way. It will be apparent to thoseskilled in the art that various modifications and variations can be madewithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents. Further, while choices formaterials and configurations may have been described above with respectto certain embodiments, one of ordinary skill in the art will understandthat the materials and configurations described are applicable acrossthe embodiments.

1. An atherectomy catheter comprising: a body having an opening; arotatable shaft coupled to the body; a tissue collection chamber coupledto the body and positioned distal to the cutting element; a cuttingelement coupled to the rotatable shaft for rotating the cutting elementabout an axis of rotation, the cutting element having a cup-shapedsurface and a cutting edge, the cup-shaped surface being configured tore-direct tissue cut by the cutting edge in a distal direction when thecup-shaped surface moves in the distal direction; and a raised elementextending outwardly from the cup-shaped surface of the cutting element,the raised element being configured to direct cut particles of materialtowards one of more of the axis of rotation of the cutting element, acatheter longitudinal axis, or the tissue collection chamber.
 2. Theatherectomy catheter of claim 1, wherein the raised element isconfigured to direct cut particles of material towards the axis ofrotation of the cutting element.
 3. The atherectomy catheter of claim 2,wherein the cutting edge is at a radially outer edge of the cuttingelement.
 4. The atherectomy catheter of claim 3, wherein the raisedelement comprises a curved raised element cutting edge.
 5. Theatherectomy catheter of claim 4, wherein the raised element comprises afirst wall that extends from the curved raised element cutting edge tothe cup-shaped surface, the first wall directing the cut particles ofmaterial towards the axis of rotation of the cutting element.
 6. Theatherectomy catheter of claim 5, wherein the first wall curves from arelatively tangential angle with the cutting edge at the radially outeredge of the cutting element to a relatively radial angle closer to theaxis of rotation of the cutting element.
 7. The atherectomy catheter ofclaim 6, wherein the raised element comprises a distal wall that extendsfrom the first, curved raised element cutting edge to a second edge, thedistal wall forming an angle of less than 90 degrees with respect to theaxis of rotation of the cutting element.
 8. The atherectomy catheter ofclaim 7, wherein the first, curved raised element cutting edge is moredistal than the second edge.
 9. The atherectomy catheter of claim 8,wherein the minimum radial distance between the first, curved raisedelement cutting edge and the cutting edge of the cutting element is lessthan the minimum radial distance between the second edge and the cuttingedge of the cutting element.
 10. The atherectomy catheter of claim 7,wherein an included angle between the first wall and the distal wall isan obtuse angle.
 11. The atherectomy catheter of claim 3, wherein theraised element is recessed proximally from the cutting edge by alongitudinal distance.
 12. The atherectomy catheter of claim 11, whereinthe raised element is recessed proximally from the cutting edge by alongitudinal distance of 0.0010 to 0.0050 inch (0.0025 to 0.0127 cm).13. The atherectomy catheter of claim 3, wherein the raised element isrecessed from the cutting edge by a radial distance of 0.0010 to 0.0050inch (0.0025 to 0.0127 cm).
 14. The atherectomy catheter of claim 2,wherein the raised element comprises a first wall that extends from araised element cutting edge to the cup-shaped surface, the first walldirecting the cut particles of material towards the axis of rotation ofthe cutting element and wherein the first wall forms an acute angle withthe cup-shaped surface to form an undercut.
 15. The atherectomy catheterof claim 14, wherein the raised element comprises a distal wall thatextends from the first raised element cutting edge to a second edge, thedistal wall forming an angle of less than 90 degrees with respect to theaxis of rotation of the cutting element.
 16. The atherectomy catheter ofclaim 15, wherein the first raised element cutting edge is more distalthan the second edge.
 17. The atherectomy catheter of claim 16, whereinthe minimum radial distance between the first raised element cuttingedge and the cutting edge of the cutting element is less than theminimum radial distance between the second edge and the cutting edge ofthe cutting element.
 18. The atherectomy catheter of claim 15, wherein awall having a rake angle is interspersed between the intersection of thefirst wall and the distal wall.
 19. The atherectomy catheter of claim18, wherein the rake angle is negative.
 20. The atherectomy catheter ofclaim 1, wherein the cup-shaped surface of the cutting element is smoothand uninterrupted throughout at least 300 degrees when viewed along theaxis of rotation of the cutting element.
 21. The atherectomy catheter ofclaim 1, wherein the cup-shaped surface of the cutting element is smoothand uninterrupted for at least 90% of the surface area of the cuttingelement when viewed along the axis of rotation of the cutting element.22. The atherectomy catheter of claim 1, wherein the cup-shaped surfaceof the cutting element has an outer radius when viewed along the axis ofrotation of the cutting element, the cup-shaped surface being continuousand uninterrupted from the axis of rotation to at least half thedistance to the outer radius.
 23. The atherectomy catheter of claim 1,further comprising a plurality of raised elements, the plurality ofraised elements altogether occupying an area less than 60 degrees andless than 5% of the surface area when viewed along the axis of rotationof the cutting element, and the cup-shaped surface being smooth anduninterrupted for at least 90% of the surface area.
 24. The atherectomycatheter of claim 1, wherein a plurality of raised elements extendoutwardly from the cup-shaped surface, the plurality of raised elementsbeing 1, 2, 3, 4, 6, or 8 raised elements.
 25. The atherectomy catheterof claim 1, wherein the cutting element is movable between a storedposition and a cutting position relative to the opening.
 26. Theatherectomy catheter of claim 25, wherein the cutting element is movedbetween the stored position and the cutting position by sliding thecutting element against a cam surface.
 27. The atherectomy catheter ofclaim 26, wherein a distal portion of the catheter relative to aproximal portion is deflected by sliding the cutting element against thecam surface.
 28. The atherectomy catheter of claim 1, wherein thecutting element is configured to oscillate in a direction substantiallyparallel to the axis of rotation of the cutting element
 29. Anatherectomy catheter comprising: a body having an opening; a rotatableshaft coupled to the body; a tissue collection chamber coupled to thebody and positioned distal to the cutting element; and a cutting elementcoupled to the rotatable shaft for rotating the cutting element about anaxis of rotation, the cutting element having a cutting edge, and thecutting element being configured to oscillate in a directionsubstantially parallel to the axis of rotation of the cutting element.30. The atherectomy catheter of claim 29, wherein the atherectomycatheter comprises a ramp having one or more recesses, the cuttingelement comprises one or more raised portions on a cam surface of thecutting element, the one or more raised portions fitting within the oneor more recesses when the raised portions and the recesses are aligned,and the raised portions leaving and entering the recesses as the cuttingelement is rotated and thereby causing the cutting element to oscillate.31. The atherectomy catheter of claim 29, wherein the atherectomycatheter comprises a ramp having one or more raised portions, thecutting element comprises one or more recesses on a cam surface of thecutting element, the one or more raised portions fitting within the oneor more recesses when the raised portions and the recesses are aligned,and the raised portions leaving and entering the recesses as the cuttingelement is rotated and thereby causing the cutting element to oscillate.32. The atherectomy catheter of claim 29, wherein the atherectomycatheter comprises a ramp having one or more raised portions, thecutting element comprises one or more raised portions on a cam surfaceof the cutting element, and the raised portions causing the cuttingelement to oscillate as the cutting element is rotated.
 33. Theatherectomy catheter of claim 29, wherein the cutting element has acup-shaped surface, the cup-shaped surface being configured to re-directtissue cut by the cutting edge in a distal direction when the cup-shapedsurface moves in the distal direction.
 34. The atherectomy catheter ofclaim 29, wherein the cutting edge is a radially outer edge of thecutting element.
 35. The atherectomy catheter of claim 29, wherein thecatheter comprises a raised element extending outwardly from thecup-shaped surface of the cutting element.
 36. The atherectomy catheterof claim 35, wherein the cutting edge is a radially outer edge of thecutting element, and the raised element is recessed proximally from thecutting edge when viewed along the axis of rotation of the cuttingelement.
 37. The atherectomy catheter of claim 29, wherein the cuttingelement is movable between a stored position and a cutting positionrelative to the opening.
 38. The atherectomy catheter of claim 37,wherein the cutting element is moved between the stored position and thecutting position by sliding the cutting element against a cam surface.39. The atherectomy catheter of claim 38, wherein a distal portion ofthe catheter relative to a proximal portion is deflected by sliding thecutting element against the cam surface.
 40. A method of removingmaterial from a body lumen, the method comprising: providing anatherectomy catheter, the atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; a cutting element coupled to the rotatable shaft for rotatingthe cutting element about an axis of rotation, the cutting elementhaving a cup-shaped surface and a cutting edge, the cup-shaped surfacebeing configured to re-direct tissue cut by the cutting edge in a distaldirection when the cup-shaped surface moves in the distal direction; anda raised element extending outwardly from the cup-shaped surface of thecutting element, the raised element being configured to direct cutparticles of material towards one of more of the axis of rotation of thecutting element, a catheter longitudinal axis, or the tissue collectionchamber; placing the catheter in the body lumen; and moving the catheterin the body lumen to contact the cutting element with the material inthe body lumen.
 41. The method of claim 40, wherein the catheter ismoved in a distal direction to contact the cutting edge with thematerial in the body lumen.
 42. The method of claim 40, wherein thecatheter is placed in the body lumen with the cutting element in thestored position and the catheter is moved to contact the material withthe cutting element in a cutting position.
 43. The method of claim 40,wherein the body lumen is a blood vessel.
 44. A method of removingmaterial from a body lumen, the method comprising: providing anatherectomy catheter, the atherectomy catheter comprising: a body havingan opening; a rotatable shaft coupled to the body; a tissue collectionchamber coupled to the body and positioned distal to the cuttingelement; and a cutting element coupled to the rotatable shaft forrotating the cutting element about an axis of rotation, the cuttingelement having a cutting edge, and the cutting element being configuredto oscillate in a direction substantially parallel to the axis ofrotation of the cutting element; placing the catheter in the body lumen;and moving the catheter in the body lumen to contact the cutting elementwith the material in the body lumen.
 45. The method of claim 44, whereinthe catheter is moved in a distal direction to contact the cutting edgewith the material in the body lumen.
 46. The method of claim 44, whereinthe catheter is placed in the body lumen with the cutting element in thestored position and the catheter is moved to contact the material withthe cutting element in a cutting position.
 47. The method of claim 44,wherein the body lumen is a blood vessel.